INTERACTIVE MAP: San Francisco's Mission Bay before the ballpark

SAN FRANCISCO (KGO) -- Did you know the ballpark you know and love is built on what used to be a lagoon?

San Francisco's Public Utilities Commission unveiled a new interactive map to show us just how much the city's shoreline has changed over the past 150 years. Blue areas were under water. The Mission Bay neighborhood, which includes AT&T Park, Fisherman's Wharf, and the Financial District was once Yerba Buena cover, a mud flat at low tide.

Crissy Field and the Marina District didn't exist. They were both under water.

The filling of land and building of piers began in the mid-1800s during the Gold Rush but it was the great quake of 1906 that put the process in overdrive.

"And then afterward the city was in ruins," said Polly Perkins of the SFPUC. "There was tons and tons of rubble and not useable material. They didn't have anywhere to put it so they actually started filling in bays like Mission Bay."